Use of categories is well known in prior art computer systems, for managing items (also called objects) of data. For example, see the article entitled “Tips for Using Microsoft Outlook To Manage Your ‘To-Do’ Lists” by Margaret Spencer Dixon, Esq. President, Spencer Consulting, published 2006 that is incorporated by reference herein in its entirety as background. For example, a user may categorize certain tasks as belonging to Project Fish and other tasks as belonging to Project Bird.
A more recent version, namely Office Outlook 2007 software (hereinafter “OUTLOOK”) available from MICROSOFT CORPORATION has a “Categorize” menu which displays six default categories that are color coded, and by default named Blue Category, Green Category etc. A user may right click on any item in OUTLOOK, such as an email message, a contact, a task or an appointment in the calendar, and select one of the categories in a predetermined list, e.g. 15 colors provided by default in OUTLOOK thereby to categorize the item. Hence, a user may categorize certain items which are urgent in the Red Category and categorize other items that are of the lowest priority in the Green Category.
Note that OUTLOOK does not appear to use a registry for the list of categories, and instead the categories seem to be stored in each user's own individual mailbox or pst file, which make them inaccessible to other users even if the other users are in the same organization. Hence, if a first user assigns a color category (e.g. Red Category) to an item and then emails that item to a second user, the second user does not appear to receive with the item, the color category (i.e. the same Red Category) assigned by the first user. Such users may share documents with one another, e.g. files may be shared, via a server of the prior art. Objects other than files, such as contacts and/or calendar appointments may be shared via a collaboration environment.
A collaboration environment 100 of the prior art (FIG. 1) typically includes a server 110 (“collaboration server”), and multiple users of clients 120-1 . . . 120-N (120 generally) interconnected via a network 112 such as the Internet, VPN, LAN, WAN or other packet switched interconnection medium. Collaboration server 110 includes a workspace 150 for providing collaborative access to a plurality of applications 130-1 . . . 130-3 (130 generally). Applications 130 provide services to the users of clients 120 via workspace 150 and network 112. Each of the applications 130 has respective storage areas 132-1 . . . 132-3 (132 generally) for storing application data 134, therefore relieving workspace 150 from storing application data 134 on behalf of users. Examples of shared application data 134 include various shared objects, for example, calendar appointments, tasks, contacts etc.
Workspace 150 of FIG. 1 includes metadata defining the application data 134 stored by applications 130 on behalf of each user of a client 120. Workspace 150 includes properties 160 that define how users of clients 120 interact with the applications 130. Properties 160 define aspects such as privileges, policies, other users and available applications 130 (services) corresponding to a particular workspace 150. Server 110 is operable by users to assign categories to shared objects in a workspace, such as contacts, files, appointments. A user may create a category and assign an item to it in one client, and server 110 shows the assigned category consistently to other users regardless of the client used to access server 110. For example, see Oracle Collaboration Suite 10g Contacts from ORACLE CORPORATION.
Nonetheless, the inventors of the current patent application believe that in prior art systems of the type shown in FIG. 1, a change in categorization of an item, is typically made by overwriting that item's old category with a new category. For example, if priority is lowered on a task previously assigned to a Red Category (for high priority tasks), then overwriting the old category with the new category requires less storage than storing the task's new category (e.g. Green Category) in addition to the old category. Improvements of the type discussed below are believed to be needed in situations that require both categories to be stored.